No, you do not.

To get started, all you need is the main UpStream plugin [from WordPress.org](https://wordpress.org/plugins/upstream/). That plugin provides key project management features and can be used with no extensions.

The UpStream extensions provide extra features, but are not essential:

- [Calendar View](https://upstreamplugin.com/extensions/calendar-view/) is needed only if you want a calendar display of Tasks and Bugs.
- [Custom Fields](https://upstreamplugin.com/extensions/custom-fields/) is needed only if you need extra information on Projects, Tasks, and Bugs.
- [Copy Project](https://upstreamplugin.com/extensions/copy-project/) is needed only if you need to create one project and duplicate it often.
- [Customizer](https://upstreamplugin.com/extensions/customizer/) is needed only if you want to change the design of your project’s frontend layout.
- [Email Notifications](https://upstreamplugin.com/extensions/email-notifications/) is needed only if you want to send reminders to users about due dates.
- [Frontend Edit](https://upstreamplugin.com/extensions/frontend-edit/) is needed only if you want to edit projects via the frontend of your site.
- [Project Timeline](https://upstreamplugin.com/extensions/project-timeline/) is needed only if you want a Gantt chart for your projects.